Well, in such fanfiction, it could be shown by team 7 members always coming to Sakura's rescue immediately. For example, if she's in a fight, they might jump in even before she has a chance to defend herself fully. They might also constantly worry about her well - being and not let her take on dangerous missions alone.
In this fanfiction, the overprotectiveness might be evident through the way they shield Sakura from any potential harm. Say, if there's a threat from an enemy, Naruto and Sasuke would form a sort of protective barrier around her without even asking if she can handle it herself. They are overly cautious about her safety all the time.
One reason could be her importance to the team. Sakura might have some special skills or knowledge that they don't want to lose. So they protect her to ensure the team's overall strength.
In the fanfiction, the overprotectiveness might show up as the gods restricting Percy's actions. They may not let him go on certain quests alone, insisting on sending a whole entourage of helpers. This could be because they see Percy as a very important asset, and they're afraid of losing him. So they overcompensate by being overly protective.
Sakura may become more confident because she has such a strong support system. Knowing that Team 7 is always there to protect her gives her the freedom to take more risks in her medical ninja skills development. For example, she might try out new experimental healing techniques without fearing for her life too much.
Well, it really depends on how the author writes it. If the overprotectiveness is written in a way that respects Marinette's agency, it could be a cute and endearing aspect of their relationship. But if it comes across as controlling, it might make Marinette resent Adrien, and then they would have to work through those issues to have a healthy relationship.
Nico might initially be frustrated. He wants to prove himself and show that he can take care of himself, but Hades' overprotectiveness holds him back.
Well, Minato might constantly be by Naruto's side in the fanfiction. He could prevent Naruto from taking on any dangerous missions, even if Naruto is capable. For example, he may interfere when Naruto tries to join a risky battle against a powerful enemy, saying it's too dangerous for him.
Well, she might constantly be by Percy's side during dangerous situations, like when they are facing monsters. She could also be very cautious about who Percy interacts with, fearing they might harm him.
However, as time goes by, Ash could come to understand that Mewtwo's overprotectiveness comes from a place of care. He might start to rely on Mewtwo in certain situations, like when they are in an extremely dangerous and unfamiliar territory. Ash could also try to communicate with Mewtwo, asking it to let him handle some things on his own while still appreciating its protection.
One possible plot could be that during a dangerous mission, Team 7 - Naruto, Sasuke, and Kakashi - constantly shield Sakura from every possible threat. For example, Naruto uses his shadow clones to form a protective barrier around her at the first sign of danger. Sasuke is always on high alert and uses his Sharingan to detect any hidden enemies that might target Sakura. And Kakashi steps in with his vast experience to make sure no harm comes to her.
One reason could be guilt. Since Minato wasn't there for Naruto when he was growing up in the original story, in the fanfiction, he might be overcompensating for that lost time. He feels like he has to make up for all those years he wasn't around to protect his son.